Verify that @Widgetset loads the right widgetset (#7885)

This is testable now that we have a separate widgetset for testing.

tests/testbench/com/vaadin/tests/components/root/TestRootWidgetset.java

@@ -3,18 +3,19 @@ package com.vaadin.tests.components.root;
 import com.vaadin.annotations.Widgetset;
 import com.vaadin.terminal.WrappedRequest;
 import com.vaadin.tests.components.AbstractTestRoot;
+import com.vaadin.tests.widgetset.server.MissingFromDefaultWidgetsetComponent;
 
-@Widgetset("invalid")
+@Widgetset("com.vaadin.tests.widgetset.TestingWidgetSet")
 public class TestRootWidgetset extends AbstractTestRoot {
 
     @Override
     protected void setup(WrappedRequest request) {
-        // Nothing here
+        addComponent(new MissingFromDefaultWidgetsetComponent());
     }
 
     @Override
     public String getTestDescription() {
-        return "This root should never load, as the widgetset can not be loaded";
+        return "This contents if this root should work as the component is present in TestingWidgetSet";
     }
 
     @Override

tests/testbench/com/vaadin/tests/components/root/TestRootWidgetset2.java

@@ -0,0 +1,24 @@
+package com.vaadin.tests.components.root;
+
+import com.vaadin.terminal.WrappedRequest;
+import com.vaadin.tests.components.AbstractTestRoot;
+import com.vaadin.tests.widgetset.server.MissingFromDefaultWidgetsetComponent;
+
+public class TestRootWidgetset2 extends AbstractTestRoot {
+
+    @Override
+    protected void setup(WrappedRequest request) {
+        addComponent(new MissingFromDefaultWidgetsetComponent());
+    }
+
+    @Override
+    public String getTestDescription() {
+        return "This contents if this root should not work as the component is not present in DefaultWidgetSet";
+    }
+
+    @Override
+    protected Integer getTicketNumber() {
+        return Integer.valueOf(7885);
+    }
+
+}

tests/testbench/com/vaadin/tests/widgetset/client/MissingFromDefaultWidgetsetConnector.java

@@ -0,0 +1,26 @@
+/* 
+@VaadinApache2LicenseForJavaFiles@
+ */
+package com.vaadin.tests.widgetset.client;
+
+import com.vaadin.terminal.gwt.client.ui.AbstractComponentConnector;
+import com.vaadin.terminal.gwt.client.ui.Connect;
+import com.vaadin.terminal.gwt.client.ui.label.VLabel;
+import com.vaadin.tests.widgetset.server.MissingFromDefaultWidgetsetComponent;
+
+@Connect(MissingFromDefaultWidgetsetComponent.class)
+public class MissingFromDefaultWidgetsetConnector extends
+        AbstractComponentConnector {
+    @Override
+    public VLabel getWidget() {
+        return (VLabel) super.getWidget();
+    }
+
+    @Override
+    protected void init() {
+        getWidget()
+                .setText(
+                        "This component is available in TestingWidgetset, but not in DefaultWidgetset");
+        super.init();
+    }
+}

tests/testbench/com/vaadin/tests/widgetset/server/MissingFromDefaultWidgetsetComponent.java

@@ -0,0 +1,10 @@
+/* 
+@VaadinApache2LicenseForJavaFiles@
+ */
+package com.vaadin.tests.widgetset.server;
+
+import com.vaadin.ui.AbstractComponent;
+
+public class MissingFromDefaultWidgetsetComponent extends AbstractComponent {
+
+}